Help! Fuel filters keep clogging - PeachParts Mercedes-Benz Forum

cyoung · #1 01-04-2010, 02:18 PM

My '78 240D is clogging up the fuel filters every 50 to 75 miles with a fine black substance. I have not run any bio-fuels in the car. Any ideas what this could be?

I have added an additional fuel filter before the primary filter so that I don't have to keep replacing the primary and secondary filters as often.

Thanks!

Cr from Texas · #2 01-04-2010, 02:22 PM

Sounds like the typical biological organism (trying to avoid the algae-fungus diversion) contamination. Soltron solved the problem for me. Do a search for Soltron and Biobor and you'll find a lot of info.

Diesel911 · #3 01-04-2010, 02:26 PM

As above but lay in a supply of Fuel Filters as the Dead Bodies may continue to clog the filters until they are out of the system.

The other alternative is to draing the Fuel tank and clean it,after assembled followed by the biocide just to be sure. More labor intensive but will reduce the cost of filters.

Cr from Texas · #4 01-04-2010, 02:34 PM

Based on product descriptions, I came to the conclusion that Biobor would more likely lead to clogging and Soltron should allow them to pass and be burned. Worked that way for me. I found both products on the shelf at West Marine (you will need to go to a marine store to find them).

cyoung · #5 01-04-2010, 02:37 PM

Thanks. I will try to get either Soltron or Biobar.

I keep the car in the garage, where the temperature is well above freezing. Would parking it outside where the temperature is below freezing help to kill the organisms?

Am I better off running the tank low before refiling (I am in the habit of filling the tank between the 1/4 and 1/2 marks) in the hopes of getting the "Dead Bodies" out quicker, or filing the tank as normal.

If I do pull the tank, should I take it to a radiator shop to be boiled out, or just clean it by the "slosh and drain" method? Also, would there be any benefit to coating the inside of the tank once I have it out?

I will replace the screen once I have the problem under control. I have laid in a bunch of filters, and have even assembled a emergency filter change kit that I keep in the car (screwdriver, filters, paper towels and rubber gloves)

Cr from Texas · #6 01-04-2010, 02:43 PM

See if you can find the products. Read and follow the instructions to the letter. Overdosing with Soltron is not a problem. Parking outside should slow the growth rate but not kill the organism. Notice how well they grow in the refrigerator once something gets contaminated.

cyoung · #7 01-04-2010, 02:57 PM

Thanks for the help. I found the Soltron at a local NAPA store, which I will pick up this afternoon.

layback40 · #8 01-04-2010, 11:21 PM

Change where you buy your fuel. Find a busy truck stop. You dont need re-contamination.

Sbean · #9 01-05-2010, 02:02 AM

When I was experiencing frequent clogging of the primary filter on my '80 300 TD when I started using WVO, I found I could re-use the filter by dumping
out the gunk. Steve

leathermang · #10 01-05-2010, 08:11 AM

Is your car a 123 model ?
If yes, you can power wash the tank with it in the vehicle... I took mine out not knowing that... the holes are positioned in prime directions for doing that...
mine was very clean inside.. it only had the black growing stuff...
after cleaning and a couple of applications of biobar or that kind of stuff have not had any more problems in that area in five years..
But periodic use of that stuff is recommended if you are in a part of the country with that problem...

cyoung · #11 02-19-2010, 09:49 PM

Follow up to contamination problem.

I have run 2 tanks of fuel with the Soltron added, and thankfully I think that I have this problem solved, as the mileage between filter changes has increased (I got 371 mile on the last filter before it clogged).

As an added benefit, my car starts much easier, and seems to be running smoother. I plan to add a dose of the Soltron for 2 more tanks, and then see what happens.

Thanks again for all the suggestions!

el sea · #12 02-19-2010, 10:25 PM

Treat your tank for the water, this is the food source for the micro growth. Adding biocide only kills the micros and then the filter is the receiver of the unwanted dead. As a professional in the tank cleaning, I give my boating customer three very strong recommendations:
1) keep your tank full or empty
2) treat your fuel by the size of the tank (if you have a twenty gallon tank and only ten gallon of fuel, treat it for the twenty) it's the dead air space in the tank that generates the condensation
3) get a six-pack & go boating (a six-pack of fuel filters)

I would also recommend the same for these older diesels.

Good Luck

vwnate1 · #13 02-20-2010, 02:12 AM

I'm assuming you used Startron from West Marine .

It's the very best .

Always fill up from below 1/4 tank and beware you may have to remove the fuel gauge's sender (it's below the first aid kit) , carefully take it apart and clean out a table spoon or so of that black sludge else the fungi will return in a few weeks .

I dosed 3 oz. of Startron with each fillup and I became very adroit at removing the clear primary intake screen and blowing it out backwards before fueling , when the tank is below 1/3 , it won't siphon fuel out whe you remove the filter

As it's now running better , consider doing a " Diesel Purge " once the intake screen remains clear for two tankfulls , it really helps .

compress ignite · #14 02-20-2010, 02:32 AM

Y'all are gonna shoot me for this one.

I've got a 1/2 full container (Vented) of #2 diesel that I've regularly treated
with Startron for 5 years, and No Fungus.
(Also No Activity,No Fuel in,No Fuel Out.)
[So, It's been subjected to Atmospheric Humidity and Condensation.]

vwnate1 · #15 02-20-2010, 02:55 AM

Why would we kill you for knowing this is good stuff ?

I don't get it .

My '84 Coupe was a Fungus Farm when I got it .